Science WorldScience World for grades 6–10 brings science to life with fascinating feature articles and hands-on activities that reinforce science concepts and help students build test-taking and critical-thinking skills.

Hurricanes

A hurricane forms when warm tropical ocean water evaporates into the air. As this air rises, the moisture condenses to form thunderclouds and rain. The process releases heat into the air all around, making it lighter and lowering the air pressure. Air then flows inward from all sides, drawn in by the area of low pressure. This air then rises and creates more thunderclouds. Earth's rotation causes the inflowing air and the huge bands of thunderstorms to spin. The center of the hurricane, which is relatively calm and rain-free, is called the hurricane's eye.

Did You Know That Hurricanes . . .

Occur between June and November

Form over warm tropical ocean water and die out over land or colder wate

Measure hundreds of kilometers in diameter

Have wind speeds of 120 kilometers per hour (74 mph) to about 242 kilometers per hour (150 mph)

Spin counterclockwise in the Northern Hemisphere but clockwise south of the equator

Can last for several days or even weeks

Usually strike the U.S. once or twice each year

Can cause billions of dollars worth of damage

Are also known as typhoons in the western Pacific Ocean and cyclones in the Southern Hemisphere